The following are proposed: 1) Estimation of the presence of Ca ATPase and Na-K ATPase in isolated transverse tubules from skeletal muscle. We will work with highly purified T-tubule preparations. The Km will be determined for Ca, Mg, ATP in Ca ATPase and for N, K, ATP in Na-K ATPase. Data will be compared with equivalent information from sarcoplasmic reticulum and terminal cisternae. Observation of ATP-induced accumulation of Ca ions and Na ions by T-tubules will be attempted. The cation and anion requirements for these processes will be investigated. 2) Location of intermediates of adrenergic stimulation of skeletal muscle. The intermediates will include beta adrenergic receptor, adenylate cyclase protein kinase mediated phosphoprotein formation and enhanced Ca accumulation. These will be located with respect to longitudinal reticulum, terminal cisternae and T-tubules. 3) Isolation of junctional factor. A factor may be extracted from isolated terminal cisternae which is required in order for terminal cisternae to aggregate with isolated T-tubules. We intend to isolate and identify this compound from the KCl extract which contains the factor. 4) Isolation of binding proteins from T-tubules and terminal cisternae. We believe that specific proteins in T-tubule and terminal cisternae vesicles attach selectively to the junction factor. We intend to identify these proteins by affinity chromatography and will attempt to isolate them from their membranes and from other proteins of the vesicles. 5) Morphological studies on the junction during fractionation and reassembly. These will be carried out on dragonfly flight muscle since they show very clear electron dense junctional feet. The formation and disruption of the diad junction in this muscle during fractionation will be monitored by electron microscopic observation and by biochemical analyses. 6) Isolation of T-tubules, diad junctions and terminal cisternae from rabbit heart. The basic approaches to isolation will be those successfully employed to isolate T-tubules from skeletal muscle. The morphological sources of the intermediates of beta-adrenergic control of Ca sequestration will be investigated.